Zoom lens and imaging apparatus

ABSTRACT

A zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming from a wide angle end to a telephoto end, the first lens group is fixed relative to an image surface, and distances between the respective lens groups change in predetermined manners. The second lens group consists of predetermined four lens components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/JP2017/009143, filed Mar. 8, 2017, the disclosure ofwhich is incorporated herein by reference in its entirety. Further, thisapplication claims priority from Japanese Patent ApplicationNo.2016-065233, filed Mar. 29, 2016, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a zoom lens suitable for an electroniccamera, such as a digital camera, a video camera, a broadcast camera, amotion-picture camera, or a surveillance camera; and also relates to animaging apparatus including the zoom lens.

2. Description of the Related Art

A zoom lens is suggested in JP2015-212723A, as a zoom lens used for anelectronic camera, such as a digital camera, a video camera, a broadcastcamera, a motion-picture camera, or a surveillance camera.

SUMMARY OF THE INVENTION

However, the F-number of the lens of JP2015-212723A at a telephoto endis not sufficiently small, and thus a zoom lens having highmagnification and a small F-number at the telephoto end is demanded.

The invention is made in light of the situations, and it is an object ofthe invention to provide a high-performance zoom lens which has highmagnification and a small F-number at a telephoto end, and whoseaberrations have been properly corrected; and an imaging apparatusincluding the zoom lens.

A zoom lens according to an aspect of the invention consists of, inorder from an object side, a first lens group having a positiverefractive power, a second lens group having a negative refractivepower, a third lens group having a positive refractive power, a fourthlens group having a positive refractive power, and a fifth lens grouphaving a positive refractive power; during zooming, the first lens groupis fixed relative to an image surface; during zooming from a wide angleend to a telephoto end, a distance between the first lens group and thesecond lens group constantly increases, a distance between the secondlens group and the third lens group constantly decreases, and a distancebetween the third lens group and the fourth lens group at the telephotoend is smaller than a distance between the third lens group and thefourth lens group at the wide angle end; the second lens group consistsof, in order from the object side, a first lens component, a second lenscomponent, a third lens component, and a fourth lens component; thefirst lens component is a 2a negative lens having a concave surface thatfaces an image side and that has a smaller absolute value of a curvatureradius than an absolute value of a curvature radius of a surface on theobject side of the 2a negative lens; the second lens component is acemented lens in which a 2bn biconcave lens and a 2bp positive meniscuslens are cemented in that order from the object side and which entirelyhas a negative refractive power; the third lens component is a cementedlens in which a 2cn biconcave lens and a 2cp positive lens are cementedin that order from the object side; and the fourth lens component is a2d negative lens having a concave surface that faces the object side andthat has a smaller absolute value of a curvature radius than an absolutevalue of a curvature radius of a surface on the image side of the 2dnegative lens.

With the zoom lens according to the invention, during zooming, the fifthlens group is preferably fixed relative to the image surface; and duringzooming from the wide angle end to the telephoto end, a 3-4 compositelens group composed of the third lens group and the fourth lens group,and the second lens group preferably simultaneously pass throughrespective points at which imaging magnifications of the 3-4 compositelens group and the second lens group are −1.

During zooming from the wide angle end to the telephoto end, thedistance between the third lens group and the fourth lens grouppreferably decreases, increases, and then decreases.

The 2a negative lens is preferably a meniscus lens.

The following conditional expression (1) is preferably satisfied, andthe following conditional expression (1-1) is further preferablysatisfied−1<(L2bpr+L2cnf)/(L2bpr-L2cnf)<1   (1), and−0.6<(L2bpr+L2cnf)/(L2bpr-L2cnf)<0.6   (1-1),where

L2bpr is a curvature radius of a surface on the image side of the 2bppositive meniscus lens, and

L2cnf is a curvature radius of a surface on the object side of the 2cnbiconcave lens.

The following conditional expressions (2) and (3) are preferablysatisfied, and the following conditional expression (2-1) and/orconditional expression (3-1) are further preferably satisfied0.2 <f2/f2a<0.6   (2),0.1<f2/f2b<0.6   (3), and0.25<f2/f2a<0.55   (2-1), and/or0.2<f2/f2b<0.5   (3-1),where

f2 is a focal length for a d-line of the second lens group,

f2a is a focal length for the d-line of the first lens component, and

f2b is a focal length for the d-line of the second lens component.

The following conditional expression (4) is preferably satisfied, andthe following conditional expression (4-1) is further preferablysatisfied−0.3<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.1   (4), and−0.2<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.12   (4-1),where

f2 is the focal length for the d-line of the second lens group,

f2cp_nd is a refractive index for the d-line of the 2cp positive lens,

f2cn_nd is a refractive index for the d-line of the 2cn biconcave lens,and

L2cnp is a curvature radius of a cemented surface of the 2cn biconcavelens and the 2cp positive lens.

The first lens group consists of, in order from the object side, a lalens group fixed relative to the image surface during focusing andhaving a negative refractive power, a 1 b lens group being movable alongan optical axis during focusing and having a positive refractive power,and a 1 c lens group fixed relative to the image surface during focusingand having a positive refractive power; and the 1 c lens group has onthe most image side four lenses of, in order from the object side, apositive lens, a cemented lens in which a negative meniscus lens havinga convex surface facing the object side and a positive lens are cementedin that order from the object side, and a positive meniscus lens havinga convex surface facing the object side.

When the first lens group is composed of the 1a lens group, the 1b lensgroup, and the 1c lens group, the following conditional expression (5)and conditional expression (6) are preferably satisfied, and thefollowing conditional expression (5-1) and/or conditional expression(6-1) are further preferably satisfied75<f1c_vd_ave<96   (5),0.5<f1c_θgF_ave<0.6   (6), and80<f1c_vd_ave<96   (5-1), and/or0.52<f1c_θgF_ave<0.56   (6-1),where

f1c_vd_ave is an average value of Abbe numbers for the d-line of thepositive lenses included in the 1 c lens group, and

f1c_θgF_ave is an average value of partial dispersion ratios of thepositive lenses included in the 1c lens group.

When the first lens group is composed of the 1a lens group, the 1b lensgroup, and the 1c lens group, the following conditional expression (7)is preferably satisfied, and the following conditional expression (7-1)is further preferably satisfied0.8<f1/f1c<1.2   (7), and0.9<f1/f1c<1.1   (7-1),where

f1 is a focal length for the d-line of the first lens group, and

f1c is a focal length for the d-line of the 1c lens group.

When the first lens group is composed of the 1a lens group, the 1b lensgroup, and the 1c lens group, the number of positive lenses included inthe 1b lens group and the 1c lens group is preferably five in total.

When the number of positive lenses included in the 1b lens group and the1c lens group is five in total, the 1b lens group may consist of, inorder from the object side, a cemented lens in which a negative meniscuslens and a biconvex lens are cemented in that order from the objectside, and a biconvex lens; and the 1c lens group may consist of, inorder from the object side, a biconvex lens, a cemented lens in which anegative meniscus lens and a positive meniscus lens are cemented in thatorder from the object side, and a positive meniscus lens.

When the number of positive lenses included in the 1b lens group and the1c lens group is five in total, the 1b lens group may consist of acemented lens in which a negative meniscus lens and a biconvex lens arecemented in that order from the object side; and the 1c lens group mayconsist of, in order from the object side, a positive lens having aconvex surface facing the object side, a positive meniscus lens, acemented lens in which a negative meniscus lens and a positive meniscuslens are cemented in that order from the object side, and a positivemeniscus lens.

When the first lens group is composed of the 1a lens group, the 1b lensgroup, and the 1c lens group, the 1a lens group preferably consists of,in order from the object side, a negative meniscus lens, a biconcavelens, and a positive lens.

An imaging apparatus according to the invention includes theabove-described zoom lens according to the invention.

The aforementioned expression “ consist of . . . ” implies that a lenshaving no power; optical elements other than a lens, such as adiaphragm, a mask, a cover glass, and a filter; a lens flange; a lensbarrel; an imaging element; a mechanism part such as a camera shakecorrection mechanism; and so forth, may be included in addition to thosedescribed as the components.

The sign of the refractive power of any of the aforementioned lensgroups, the sign of the refractive power of any of the aforementionedlenses, and the surface shape of any of the lenses are considered in aparaxial region as far as an aspherical surface is included. All theaforementioned conditional expressions use the d-line (wavelength of587.6 nm) as the reference and use values in focus at infinity unlessotherwise noted.

A zoom lens according to the invention consists of, in order from anobject side, a first lens group having a positive refractive power, asecond lens group having a negative refractive power, a third lens grouphaving a positive refractive power, a fourth lens group having apositive refractive power, and a fifth lens group having a positiverefractive power; during zooming, the first lens group is fixed relativeto an image surface; during zooming from a wide angle end to a telephotoend, a distance between the first lens group and the second lens groupconstantly increases, a distance between the second lens group and thethird lens group constantly decreases, and a distance between the thirdlens group and the fourth lens group at the telephoto end is smallerthan a distance between the third lens group and the fourth lens groupat the wide angle end; the second lens group consists of, in order fromthe object side, a first lens component, a second lens component, athird lens component, and a fourth lens component; the first lenscomponent is a 2a negative lens having a concave surface that faces animage side and that has a smaller absolute value of a curvature radiusthan an absolute value of a curvature radius of a surface on the objectside of the 2a negative lens; the second lens component is a cementedlens in which a 2bn biconcave lens and a 2bp positive meniscus lens arecemented in that order from the object side and which entirely has anegative refractive power; the third lens component is a cemented lensin which a 2cn biconcave lens and a 2cp positive lens are cemented inthat order from the object side; and the fourth lens component is a 2dnegative lens having a concave surface that faces the object side andthat has a smaller absolute value of a curvature radius than an absolutevalue of a curvature radius of a surface on the image side of the 2dnegative lens. Thus, the zoom lens can be a high-performance zoom lenswhich has high magnification and a small F-number at the telephoto end,and whose aberrations have been properly corrected.

An imaging apparatus according to the invention includes the zoom lensaccording to the invention, and thus an image with high magnificationand high image quality can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides cross-sectional views illustrating a lens configurationof a zoom lens according to an embodiment (common to Example 1) of theinvention;

FIG. 2 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 2 of the invention;

FIG. 3 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 3 of the invention;

FIG. 4 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 4 of the invention;

FIG. 5 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 5 of the invention;

FIG. 6 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 6 of the invention;

FIG. 7 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 7 of the invention;

FIG. 8 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 8 of the invention;

FIG. 9 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 9 of the invention;

FIG. 10 provides cross-sectional views illustrating a lens configurationof a zoom lens according to Example 10 of the invention;

FIG. 11 provides aberration diagrams of the zoom lens according toExample 1 of the invention;

FIG. 12 provides aberration diagrams of the zoom lens according toExample 2 of the invention;

FIG. 13 provides aberration diagrams of the zoom lens according toExample 3 of the invention;

FIG. 14 provides aberration diagrams of the zoom lens according toExample 4 of the invention;

FIG. 15 provides aberration diagrams of the zoom lens according toExample 5 of the invention;

FIG. 16 provides aberration diagrams of the zoom lens according toExample 6 of the invention;

FIG. 17 provides aberration diagrams of the zoom lens according toExample 7 of the invention;

FIG. 18 provides aberration diagrams of the zoom lens according toExample 8 of the invention;

FIG. 19 provides aberration diagrams of the zoom lens according toExample 9 of the invention;

FIG. 20 provides aberration diagrams of the zoom lens according toExample 10 of the invention; and

FIG. 21 is a brief configuration diagram of an imaging apparatusaccording to an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the invention is described below in detail withreference to the drawings. FIG. 1 provides cross-sectional viewsillustrating a lens configuration of a zoom lens according to anembodiment of the invention. A configuration example illustrated in FIG.1 is common to the configuration of a zoom lens according to Example 1which will be described later. In FIG. 1, the left side is an objectside and the right side is an image side. An illustrated aperturediaphragm St does not necessarily indicate the size or shape, butindicates the position on an optical axis Z. FIG. 1 also illustrates anarrow indicative of a movement locus of each lens group during zoomingfrom a wide angle end to a telephoto end, a point at which an imagingmagnification is −1 (a horizontal dotted line with β=−1 in the drawing),axial rays wa, and rays wb at the maximum angle of view.

The zoom lens according to this embodiment consists of, in order fromthe object side, a first lens group G1 having a positive refractivepower, a second lens group G2 having a negative refractive power, athird lens group G3 having a positive refractive power, a fourth lensgroup G4 having a positive refractive power, an aperture diaphragm St,and a fifth lens group G5 having a positive refractive power; and thezoom lens is configured such that, during zooming, the first lens groupG1 is fixed relative to an image surface Sim, and during zooming fromthe wide angle end to the telephoto end, the distance between the firstlens group G1 and the second lens group G2 constantly increases, thedistance between the second lens group G2 and the third lens group G3constantly decreases, and the distance between the third lens group G3and the fourth lens group G4 at the telephoto end is smaller than thatat the wide angle end.

When the zoom lens is applied to an imaging apparatus, it is preferableto arrange a cover glass, a prism, and/or any of various filters, suchas an infrared cut filter or a low pass filter, between the opticalsystem and the image surface Sim in accordance with a cameraconfiguration on which the lens is mounted. Thus, FIG. 1 illustrates anexample in which parallel-plane-shaped optical members PP1 and PP2 thatexpect the above-listed components are arranged between the lens systemand the image surface Sim.

With this configuration, the third lens group G3 and the fourth lensgroup G4 correct a variation in position of the image surface caused byzooming with respect to the second lens group G2 that acts on zooming,and the third lens group G3 and the fourth lens group G4 relativelymove. Thus, field curvature during zooming can be corrected and avariation in spherical aberration during zooming can be properlycorrected.

The third lens group G3 and the fourth lens group G4 are configured tomove so that the distance therebetween on a telephoto side is smallerthan that on a wide angle side. The movement range of the second lensgroup G2 on the telephoto side can be large, and the refractive power ofthe second lens group G2 can be suppressed. Thus, a variation inaberration caused by zooming can be suppressed.

The second lens group G2 consists of, in order from the object side, afirst lens component, a second lens component, a third lens component,and a fourth lens component; and the first lens component is a 2anegative lens L2 a having a concave surface that faces the image sideand that has a smaller absolute value of a curvature radius than anabsolute value of a curvature radius of a surface on the object side ofthe 2a negative lens L2 a; the second lens component is a cemented lensin which a 2bn biconcave lens L2bn and a 2bp positive meniscus lens L2bpare cemented in that order from the object side and which entirely has anegative refractive power; the third lens component is a cemented lensin which a 2cn biconcave lens L2cn and a 2cp positive lens L2cp arecemented in that order from the object side; and the fourth lenscomponent is a 2d negative lens L2 d having a concave surface that facesthe object side and that has a smaller absolute value of a curvatureradius than an absolute value of a curvature radius of a surface on theimage side of the 2d negative lens L2 d.

If the second lens group G2 has more than four lens components, themovement range of the second lens group G2 may be hardly secured. If thesecond lens group G2 has less than four lens components, it is difficultto suppress aberrations. Thus, with the four lens components, themovement range of the second lens group G2 can be secured andaberrations can be suppressed.

To attain high magnification, the principal point position of the secondlens group G2 is required to be located at a position closer to theobject side, and hence a negative lens is required to be added to thesecond lens group G2.

Since the first lens component has the above-described configuration,occurrence of distortion and astigmatism on the wide angle side can besuppressed.

The principal point position can be located closer to the object side byarranging the negative lens on the image side of the second lenscomponent; however, lateral chromatic aberration likely occurs on thewide angle side. Owing to this, since the second lens component is thecemented lens of the 2bn biconcave lens L2bn and the 2bp positivemeniscus lens L2bp as described above and the cemented lens entirely hasthe negative refractive power, the lateral chromatic aberration can becorrected while the principal point position is located closer to theobject side. Also, if the 2bp positive meniscus lens L2bp has a concavesurface on the image side, this is advantageous to widening the angle ofview.

Since the second lens component has the concave surface on the imageside, for the third lens component, by arranging on the most object sidea lens having a concave surface on the object side, occurrence ofspherical aberration on the telephoto side can be suppressed. Also, ifthe cemented lens of the 2cn biconcave lens L2cn and the 2cp positivelens L2cp is employed, axial chromatic aberration on the telephoto sidecan be corrected.

Since the fourth lens component has the concave surface on the objectside, the fourth lens component contributes to correcting astigmatismthat occurs due to the first lens group G1 on the wide angle side whilesuppressing occurrence of spherical aberration on the telephoto side.Also, since the negative lens is employed, the fourth lens componentcontributes to enhancing the negative refractive power of the entiresecond lens group G2.

With the zoom lens according to this embodiment, during zooming, thefifth lens group G5 is preferably fixed relative to the image surfaceSim, and during zooming from the wide angle end to the telephoto end, a3-4 composite lens group composed of the third lens group G3 and thefourth lens group G4, and the second lens group G2 preferablysimultaneously pass through respective points at which imagingmagnifications of the 3-4 composite lens group and the second lens groupG2 are −1. With this configuration, the third lens group G3 does notreturn to the image side and a large zoom ratio can be obtained duringzooming from the wide angle end to the telephoto end.

During zooming from the wide angle end to the telephoto end, thedistance between the third lens group G3 and the fourth lens group G4preferably decreases, increases, and then decreases. With thisconfiguration, a variation in field curvature at an intermediate focallength can be suppressed.

The 2a negative lens is preferably a meniscus lens. Since the 2anegative lens has a convex surface on the object side and a concavesurface on the image side, this is advantageous to suppressingdistortion and astigmatism on the wide angle side, and advantageous tosuppressing spherical aberration on the telephoto side.

The following conditional expression (1) is preferably satisfied. Aslong as below the upper limit of the conditional expression (1),distortion and astigmatism on the wide angle side can be suppressed. Aslong as above the lower limit of the conditional expression (1),spherical aberration on the telephoto side can be suppressed. If thefollowing conditional expression (1-1) is satisfied, further propercharacteristics can be obtained.−1<(L2bpr+L2cnf)/(L2bpr−L2cnf)<1   (1), and−0.6<(L2bpr+L2cnf)/(L2bpr−L2cnf)<0.6   (1-1),where

L2bpr is a curvature radius of a surface on the image side of the 2bppositive meniscus lens, and

L2cnf is a curvature radius of a surface on the object side of the 2cnbiconcave lens.

The following conditional expressions (2) and (3) are preferablysatisfied. By setting values not to be equal to or more than the upperlimits of the conditional expressions (2) and (3), distortion andastigmatism on the wide angle side can be suppressed. By setting valuesnot to be equal to or less than the lower limits of the conditionalexpressions (2) and (3), the negative refractive power increases, andthe principal point position can be located closer to the object side.If the following conditional expression (2-1) and/or conditionalexpression (3-1) is satisfied, further proper characteristics can beobtained.0.2<f2/f2a<0.6   (2),0.1<f2/f2b<0.6   (3), and0.25<f2/f2a<0.55   (2-1), and/or0.2<f2/f2b<0.5   (3-1),where

f2 is a focal length for a d-line of the second lens group,

f2a is a focal length for the d-line of the first lens component, and

f2b is a focal length for the d-line of the second lens component.

The following conditional expression (4) is preferably satisfied. If theconditional expression (4) is satisfied, at a cemented surface of the2cn biconcave lens L2cn and the 2cp positive lens L2cp, sphericalaberration on the telephoto side can be properly corrected. If thefollowing conditional expression (4-1) is satisfied, further propercharacteristics can be obtained.−0.3<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.1   (4), and−0.2<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.12   (4-1),where

f2 is the focal length for the d-line of the second lens group,

f2cp_nd is a refractive index for the d-line of the 2cp positive lens,

f2cn_nd is a refractive index for the d-line of the 2cn biconcave lens,and

L2cnp is a curvature radius of a cemented surface of the 2cn biconcavelens and the 2cp positive lens.

The first lens group G1 preferably consists of, in order from the objectside, a 1 a lens group G1 a fixed relative to the image surface Simduring focusing and having a negative refractive power, a 1 b lens groupG1 b being movable along the optical axis during focusing and having apositive refractive power, and a 1 c lens group G1 c fixed relative tothe image surface Sim during focusing and having a positive refractivepower; and the 1 c lens group G1 c preferably has on the most image sidefour lenses of, in order from the object side, a positive lens, acemented lens in which a negative meniscus lens having a convex surfacefacing the object side and a positive lens are cemented in that orderfrom the object side, and a positive meniscus lens having a convexsurface facing the object side.

Since the first lens group G1 is composed of the above-described 1 alens group G1 a, 1 b lens group G1 b, and 1 c lens group G1 c, thiscontributes to reduction in spherical aberration, axial chromaticaberration, and variation in the angle of view caused by downsizingand/or focusing.

Since the 1 c lens group G1 c has the above-described configuration andspherical aberration of marginal rays on the telephoto side is properlycorrected, the F-number can be decreased while high magnification isattained. Specifically, marginal rays on the telephoto side becomeconvergent rays due to the positive lens on the most object side amongthe four lenses. The convergent rays are incident on the negativemeniscus lens next to that positive lens, and hence spherical aberrationis not excessively corrected. The convergent rays are also incident onthe positive meniscus lens, and hence spherical aberration is notexcessively corrected. Thus, the spherical aberration can be properlycorrected.

When the first lens group G1 is composed of the 1 a lens group G1 a ,the 1 b lens group G1 b, and the 1 c lens group G1 c, the followingconditional expressions (5) and (6) are preferably satisfied. If Abbenumbers and partial dispersion ratios of the positive lenses included inthe 1 c lens group G1 c satisfy the conditional expressions (5) and (6),axial chromatic aberration and secondary spectrum on the telephoto sidecan be simultaneously properly corrected. If the following conditionalexpression (5-1) and/or conditional expression (6-1) are satisfied,further proper characteristics can be obtained.75<f1c_vd_ave<96   (5),0.5<f1c_θgF_ave<0.6   (6), and80<f1c_vd_ave<96   (5-1), and/or0.52<f1c_θgF_ave<0.56   (6-1),where

f1c_vd_ave is an average value of Abbe numbers for the d-line of thepositive lenses included in the 1 c lens group, and

f1c_θgF_ave is an average value of partial dispersion ratios of thepositive lenses included in the 1 c lens group.

When the first lens group G1 is composed of the 1 a lens group G1 a ,the 1 b lens group G1 b, and the 1 c lens group G1 c, the followingconditional expression (7) is preferably satisfied. As long as below theupper limit of the conditional expression (7), spherical aberration canbe properly corrected. As long as above the lower limit of theconditional expression (7), the back focus of the first lens group G1can be increased, and even for a high-magnification lens, the power ofthe second lens group G2 can be suppressed. Thus, occurrence ofaberrations due to the second lens group G2 can be suppressed. If thefollowing conditional expression (7-1) is satisfied, further propercharacteristics can be obtained.0.8<f1/f1c<1.2   (7), and0.9<f1/f1c<1.1   (7-1),where

f1 is a focal length for the d-line of the first lens group, and

f1c is a focal length for the d-line of the 1 c lens group.

When the first lens group G1 is composed of the 1 a lens group G1 a ,the 1 b lens group G1 b, and the 1 c lens group G1 c, sphericalaberration can be more easily corrected as the number of positive lensesincluded in the 1 b lens group G1 b and the 1 c lens group G1 cincreases; however, it is difficult to secure a stroke during focusing.Thus, the number of positive lenses included in the 1 b lens group G1 band the 1 c lens group G1 c is preferably five in total. With thisconfiguration, the spherical aberration can be corrected and the strokeduring focusing can be secured.

When the number of positive lenses included in the 1 b lens group G1 band the 1 c lens group G1 c is five in total, the 1 b lens group G1 bmay consist of, in order from the object side, a cemented lens in whicha negative meniscus lens and a biconvex lens are cemented in that orderfrom the object side, and a biconvex lens; and the 1 c lens group G1 cmay consist of, in order from the object side, a biconvex lens, acemented lens in which a negative meniscus lens and a positive meniscuslens are cemented in that order from the object side, and a positivemeniscus lens.

With this configuration, the power of the 1 b lens group G1 b can beincreased, and the height of marginal rays incident on the 1 c lensgroup G1 c can be decreased. Thus, even when the F-number is small, theconfiguration is advantageous to downsizing.

When the number of positive lenses included in the 1 b lens group G1 band the 1 c lens group G1 c is five in total, the 1 b lens group G1 bmay consist of a cemented lens in which a negative meniscus lens and abiconvex lens are cemented in that order from the object side; and the 1c lens group G1 c may consist of, in order from the object side, apositive lens having a convex surface facing the object side, a positivemeniscus lens, a cemented lens in which a negative meniscus lens and apositive meniscus lens are cemented in that order from the object side,and a positive meniscus lens.

With this configuration, the power of the 1 c lens group G1 c can beincreased, and the power of the 1 b lens group G1 b can be decreased.Thus, aberrations during variation in focus, in particular, variation inspherical aberration can be suppressed.

When the first lens group G1 is composed of the 1a lens group G1 a, the1 b lens group G1 b, and the 1 c lens group G1 c, the 1a lens group G1 apreferably consists of, in order from the object side, a negativemeniscus lens, a biconcave lens, and a positive lens. With thisconfiguration, distortion on the wide angle side, and sphericalaberration on the telephoto side can be properly corrected.

When the first lens group G1 is composed of the 1 a lens group G1 a, the1 b lens group G1 b, and the 1 c lens group G1 c, the 1 a lens group G1a preferably consists of, in order from the object side, a firstnegative lens, a second negative lens, and a positive lens, andpreferably satisfies the following conditional expression (8). Since the1a lens group G1 a has the above-described configuration, the angle ofchief rays of a peripheral angle of view incident on the 1 b lens groupG1 b can be decreased, and occurrence of astigmatism due to the 1 b lensgroup G1 b and later can be reduced. Since the conditional expression(8) is satisfied, variation in field curvature during zooming can bereduced, and further spherical aberration on the telephoto side can beaccommodated within a proper range. If the following conditionalexpression (8-1) is satisfied, further proper characteristics can beobtained.−0.8<(L1ar+L1bf)/(L1ar−L1bf)<−0.04   (8), and−0.5<(L1ar+L1bf)/(L1ar−L1bf)<−0.04   (8-1),where

L1ar is a curvature radius of a surface on the image side of the firstnegative lens, and

L1bf is a curvature radius of a surface on the object side of the secondnegative lens.

When the 1 a lens group G1 a consists of, in order from the object side,the first negative lens, the second negative lens, and the positivelens, the 1 a lens group G1 a preferably satisfies the followingconditional expression (9). As long as below the upper limit of theconditional expression (9), spherical aberration on the telephoto sidecan be reduced. As long as above the lower limit of the conditionalexpression (9), a sufficient negative power can be given to an air lensthat is formed between the first negative lens and the second negativelens, and hence spherical aberration on the telephoto side can bereduced. If the following conditional expression (9-1) is satisfied,further proper characteristics can be obtained.0.04<d2/tt1<0.15   (9), and0.06<d2/tt1<0.12   (9-1),where

d2 is a distance between the first negative lens and the second negativelens, and

tt1 is a length on the optical axis of the first lens group.

While FIG. 1 illustrates the example in which the optical members PP1and PP2 are arranged between the lens system and the image surface Sim,instead of arranging any of various filters, such as a low pass filteror one that cuts a specific wavelength range, between the lens systemand the image surface Sim, such various filters may be arranged betweenrespective lenses, or a lens surface of any of the lenses may be treatedwith a coating having an effect similar to those of the various filters.

Next, numerical examples of the zoom lens according to the invention aredescribed.

A zoom lens according to Example 1 is described first. FIG. 1 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 1. In FIG. 1, and FIGS. 2 to 10 corresponding toExamples 2 to 10, the left side is an object side and the right side isan image side. An illustrated aperture diaphragm St does not necessarilyindicate the size or shape, but indicates the position on an opticalaxis Z. FIG. 1 also illustrates an arrow indicative of a movement locusof each lens group during zooming from a wide angle end to a telephotoend, a point at which an imaging magnification is −1 (a horizontaldotted line with β=−1 in the drawing), axial rays wa, and rays wb at themaximum angle of view.

The zoom lens according to Example 1 is composed of, in order from theobject side, a first lens G1 consisting of ten lenses of a lens L1 a toa lens L1 j and entirely having a positive refractive power, a secondlens group G2 consisting of six lenses of a lens L2 a to a lens L2 d andentirely having a negative refractive power, a third lens group G3consisting of three lenses of a lens L3 a to a lens L3 c and entirelyhaving a positive refractive power, a fourth lens group G4 consisting ofthree lenses of a lens L4 a to a lens L4 c and entirely having apositive refractive power, and a fifth lens group G5 consisting offifteen lenses of a lens L5a to a lens L5 o and entirely having apositive refractive power.

The first lens group G1 is composed of a 1a lens group G1 a consistingof three lenses of the lens L1 a to the lens L1 c, a 1 b lens group G1 bconsisting of three lenses of the lens L1 d to the lens L 1 f, and a 1 clens group G1 c consisting of four lenses of the lens L1 g to the lensL1 j.

Table 1 shows basic lens data of the zoom lens according to Example 1,Table 2 shows data relating to specifications, Table 3 shows datarelating to surface distances that change during zooming, and Table 4shows data relating to aspherical coefficients. The meaning of referencesigns in the table are exemplarily described below according to Example1, and reference signs according to Examples 2 to 10 are basicallysimilar to those according to Example 1.

In the lens data in Table 1, the column of surface number indicatessurface numbers that sequentially increase toward the image side while asurface of a component on the most object side is counted as the firstsurface, the column of curvature radius indicates a curvature radius ofeach surface, and the column of surface distance indicates a distancebetween each surface and a surface next thereto on the optical axis Z.Also, the column of nd indicates a refractive index for the d-line(wavelength of 587.6 nm) of each optical element, the column of vdindicates an Abbe number for the d-line (wavelength of 587.6 nm) of eachoptical element, and the column of θgF indicates a partial dispersionratio of each optical element.

The partial dispersion ratio θgF is expressed by the followingexpressionθgF=(ng−nF)/(nF−nC)where

ng is a refractive index for a g-line,

nF is a refractive index for an F-line, and

nC is a refractive index for a C-line.

In this case, the sign of the curvature radius is positive when thesurface shape is convex on the object side, and negative when thesurface shape is convex on the image side. The basic lens data includesthe aperture diaphragm St and the optical members PP1 and PP2. A word“diaphragm” together with the surface number thereof is written in acell of a surface corresponding to the aperture diaphragm St in thecolumn of surface number. In the lens data in Table 1, DD [surfacenumber] is written in a cell of the column of surface distance if thedistance changes during zooming. The numerical value corresponding to DD[surface number] is shown in Table 3.

For data relating to specifications in Table 2, values of zoommagnification, focal length f, F-number FNo., and total angle of view 2ωare shown.

In the basic lens data, data relating to specifications, and datarelating to surface distances that change, the unit of angle is degree,and the unit of length is millimeter; however, since the optical systemcan be used although the optical system is proportionally expanded orproportionally contracted, other suitable units may be used.

In the lens data in Table 1, an asterisk * is added to a surface numberof an aspherical surface, and a numerical value of a paraxial curvatureradius is indicated as a curvature radius of the aspherical surface. Thedata relating to aspherical coefficients in Table 4 indicates a surfacenumber of an aspherical surface, and an aspherical coefficient relatingto the aspherical surface. A numerical value “E±n” (n is an integer) ofan aspherical coefficient represents “×10^(±n).” The asphericalcoefficient is a value of each of coefficients KA, Am (m=3 . . . 16)expressed by the following aspherical surface expressionZd=C·h ²/{1+(1−KA·C ₂ ·h ²)^(1/2)}+ΣAm·h^(m)where

Zd is an aspherical surface depth (a length of a perpendicular lineextending from a point on an aspherical surface at a height h to a planeperpendicular to the optical axis with which the vertex of theaspherical surface comes into contact),

h is a height (a distance from the optical axis),

C is a reciprocal of a paraxial curvature radius, and

KA, Am each are an aspherical coefficient (m=3 . . . 16).

TABLE 1 Example 1, lens data (nd, νd for d-line) Surface CurvatureSurface number radius distance nd νd θgF  1 −13378.35006 5.977 1.7725049.60 0.55212  2 506.33763 16.475  3 −584.49773 4.800 1.80400 46.580.55730  4 335.43813 2.500  5 349.09925 12.000 1.84139 24.56 0.61274  68435.34081 4.877  7 7849.07545 5.000 1.80000 29.84 0.60178  8 439.8260818.270 1.49700 81.54 0.53748  9 −444.99046 0.125  10 1000.00000 10.8771.63246 63.77 0.54215  11 −1249.86489 34.999  12 336.67292 23.0001.43387 95.18 0.53733  13 −555.44540 1.838  14 224.29284 6.264 1.6398034.47 0.59233  15 143.35462 28.031 1.43875 94.94 0.53433  16 8626.608793.144  17 176.57760 17.500 1.49700 81.54 0.53748  18 475.02631 DD [18] 19 182.61414 4.500 1.95375 32.32 0.59015  20 86.38802 12.791  21−331.30207 3.073 1.55032 75.50 0.54001  22 61.69495 4.501 1.54814 45.780.56859  23 78.10163 9.831  24 −145.36707 2.145 1.49700 81.54 0.53748 25 96.62937 7.000 1.84139 24.56 0.61274  26 −687.33596 5.926  27−76.16819 2.130 1.43875 94.94 0.53433  28 1644.59414 DD [28]  294104.02749 7.091 1.43875 94.66 0.53402  30 −137.72084 0.177  312020.97885 7.824 1.43875 94.66 0.53402  32 −125.76283 2.257 1.9469232.77 0.58862  33 −185.59421 DD [33]  34 124.45199 6.891 1.80390 32.490.59305  35 90.80287 10.021 1.43875 94.66 0.53402  36 −49972.97817 2.118 37 817.29840 6.060 1.43875 94.66 0.53402 *38 −343.72331 DD [38]  39 ∞7.705 (diaphragm)  40 −170.68031 4.420 1.51793 61.26 0.54257  411424.66641 1.393  42 854.58215 4.351 1.84139 24.56 0.61274  43−298.35856 3.656 1.83481 42.72 0.56486  44 408.16101 22.581  45−124.70799 2.963 1.63723 35.15 0.58660  46 545.65832 5.104 1.84139 24.560.61274  47 −188.00072 0.570  48 59.62634 5.814 1.73532 53.96 0.54449 49 1199.51213 3.520 1.72395 29.02 0.60094  50 86.05183 19.251  51144.47442 7.880 1.74356 40.77 0.57416  52 −63.44339 2.500 1.92486 36.380.57719  53 99.00655 14.855  54 342.36858 5.042 1.84139 24.56 0.61274 55 −97.66651 13.086  56 222.75255 4.531 1.52189 50.90 0.55751  5721.13645 6.601 1.49700 81.54 0.53748  58 48.14182 8.035  59 95.087016.958 1.49700 81.54 0.53748  60 −37.48307 2.876 1.95375 32.32 0.59015 61 −260.67641 9.976  62 55.91542 4.808 1.53515 57.90 0.54800  63−387.96848 2.000  64 ∞ 1.500 1.51633 64.14 0.53531  65 ∞ 0.000  66 ∞3.690 1.51633 64.14 0.53531  67 ∞ 35.589

TABLE 2 Example 1, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 19.8 magnification f′ 34.993 134.373692.862 FNo. 2.85 2.85 4.85 2ω[°] 44.8 11.8 2.4

TABLE 3 Example 1, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 5.430 85.787 118.419 DD [28] 231.414 131.867 2.255DD [33] 24.452 5.861 2.307 DD [38] 2.654 40.435 140.970

TABLE 4 Example 1, aspherical coefficient Surface number 38 KA−6.0660447E+00 A3   0.0000000E+00 A4 −2.8516819E−09 A5 −3.7645381E−10 A6  5.1922095E−11 A7 −1.9515833E−13 A8   4.9687016E−14 A9 −1.0574536E−14A10   2.5263117E−17 A11   2.5847685E−17 A12 −7.1492956E−19 A13  3.0977491E−21 A14 −1.5830950E−22 A15   9.3185221E−24 A16−1.0801038E−25

FIG. 11 provides aberration diagrams of the zoom lens according toExample 1. Spherical aberration, astigmatism, distortion, and lateralchromatic aberration at the wide angle end are shown in FIG. 11 in orderfrom the left side in the upper section. Spherical aberration,astigmatism, distortion, and lateral chromatic aberration at anintermediate position are shown in FIG. 11 in order from the left sidein the middle section. Spherical aberration, astigmatism, distortion,and lateral chromatic aberration at the telephoto end are shown in FIG.11 in order from the left side in the lower section. The aberrationdiagrams show states when the object distance is infinity. Theaberration diagrams showing spherical aberration, astigmatism, anddistortion show aberrations using the d-line (wavelength of 587.6 nm) asthe reference wavelength. The spherical aberration diagram showsaberrations for the d-line (wavelength of 587.6 nm), C-line (wavelengthof 656.3 nm), F-line (wavelength of 486.1 nm), and g-line (wavelength of435.8 nm) by respectively using solid line, long dotted line, shortdotted line, and gray solid line. The astigmatism diagram showsaberrations in a sagittal direction and a tangential direction byrespectively using solid line and short dotted line. The lateralchromatic aberration diagram shows aberrations for the C-line(wavelength of 656.3 nm), F-line (wavelength of 486.1 nm), and g-line(wavelength of 435.8 nm) by respectively using long dotted line, shortdotted line, and gray solid line. Note that FNo. in the sphericalaberration diagram indicates an F-number, and co in the other aberrationdiagrams indicates a half angle of view.

A zoom lens according to Example 2 is described next. FIG. 2 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 2. The zoom lens according to Example 2 has thesame lens number configuration as that of the zoom lens according toExample 1. Table 5 shows basic lens data of the zoom lens according toExample 2, Table 6 shows data relating to specifications, Table 7 showsdata relating to surface distances that change, and Table 8 shows datarelating to aspherical coefficients. FIG. 12 shows aberrations.

TABLE 5 Example 2, lens data (nd, νd for d-line) Surface CurvatureSurface number radius distance nd νd θgF  1 −17374.27699 4.954 1.7725049.60 0.55212  2 515.52725 16.475  3 −565.78121 4.800 1.80400 46.580.55730  4 334.28184 2.500  5 348.58721 12.000 1.84139 24.56 0.61274  67335.08162 4.857  7 8100.03388 5.000 1.80000 29.84 0.60178  8 441.5792618.270 1.49700 81.54 0.53748  9 −459.45313 0.125  10 999.62577 10.8631.63246 63.77 0.54215  11 −1249.85366 34.988  12 331.41864 23.0001.43387 95.18 0.53733  13 −555.43460 1.844  14 231.27593 6.246 1.7204734.71 0.58350  15 143.34892 28.057 1.49700 81.54 0.53748  16 4763.221083.150  17 179.29715 17.500 1.49700 81.54 0.53748  18 457.42906 DD [18] 19 182.44776 4.500 1.95375 32.32 0.59015  20 86.51118 12.791  21−334.16437 3.072 1.55032 75.50 0.54001  22 61.82805 4.500 1.54814 45.780.56859  23 78.16316 9.822  24 −145.45264 2.145 1.49700 81.54 0.53748 25 96.79029 7.009 1.84139 24.56 0.61274  26 −694.72543 5.941  27−76.19334 2.141 1.43875 94.94 0.53433  28 1736.83551 DD [28]  294270.48200 7.105 1.43875 94.66 0.53402  30 −137.86493 0.194  312057.62397 7.841 1.43875 94.66 0.53402  32 −126.04188 2.251 1.9470932.76 0.58864  33 −185.50599 DD [33]  34 124.39046 6.894 1.80391 32.490.59304  35 90.81996 10.020 1.43875 94.66 0.53402  36 −169144.053042.114  37 824.45845 6.056 1.43875 94.66 0.53402 *38 −346.58355 DD [38] 39 ∞ 7.698 (diaphragm)  40 −170.85337 4.409 1.51792 61.26 0.54256  411412.02444 1.380  42 849.25112 4.339 1.84139 24.56 0.61274  43−295.14207 3.651 1.83481 42.72 0.56486  44 407.32585 22.575  45−124.60852 2.955 1.63728 35.13 0.58662  46 549.68268 5.099 1.84139 24.560.61274  47 −188.55815 0.573  48 59.52609 5.815 1.73548 53.96 0.54449 49 1254.27053 3.520 1.72380 29.01 0.60096  50 86.04201 19.247  51144.55821 7.876 1.74390 40.78 0.57413  52 −63.49507 2.500 1.92466 36.380.57721  53 99.04128 14.838  54 347.50320 5.029 1.84139 24.56 0.61274 55 −97.91525 13.073  56 222.40660 4.518 1.52047 51.16 0.55705  5721.11965 6.594 1.49700 81.54 0.53748  58 48.22752 8.032  59 94.795226.951 1.49700 81.54 0.53748  60 −37.49466 2.868 1.95375 32.32 0.59015 61 −259.55822 9.975  62 55.77235 4.807 1.53634 57.80 0.54818  63−380.90253 2.000  64 ∞ 1.500 1.51633 64.14 0.53531  65 ∞ 0.000  66 ∞3.690 1.51633 64.14 0.53531  67 ∞ 35.589

TABLE 6 Example 2, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 19.8 magnification f′ 34.992 134.370692.844 FNo. 2.85 2.85 4.85 2ω[°] 44.8 11.8 2.4

TABLE 7 Example 2, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 7.414 87.953 120.637 DD [28] 231.897 132.146 2.241DD [33] 24.482 5.853 2.287 DD [38] 2.530 40.369 141.157

TABLE 8 Example 2, aspherical coefficient Surface number 38 KA−6.0661247E+00 A3   0.0000000E+00 A4 −6.0498397E−10 A5 −3.9242470E−10 A6  4.2998199E−11 A7   6.5777538E−15 A8   6.1474104E−14 A9 −1.0495812E−14A10   1.5144561E−17 A11   2.4967345E−17 A12 −7.1763341E−19 A13  5.0602365E−21 A14 −1.7779216E−22 A15   8.3996059E−24 A16−9.3643011E−26

A zoom lens according to Example 3 is described next. FIG. 3 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 3. The zoom lens according to Example 3 has thesame lens number configuration as that of the zoom lens according toExample 1. Table 9 shows basic lens data of the zoom lens according toExample 3, Table 10 shows data relating to specifications, Table 11shows data relating to surface distances that change, and Table 12 showsdata relating to aspherical coefficients. FIG. 13 shows aberrations.

TABLE 9 Example 3, lens data (nd, νd for d-line) Surface CurvatureSurface number radius distance nd νd θgF  1 31335.06747 5.980 1.7725049.60 0.55212  2 489.39985 16.475  3 −607.98263 4.800 1.80400 46.580.55730  4 338.23443 2.500  5 351.80001 12.000 1.84139 24.56 0.61274  65645.25277 4.829  7 5037.54253 5.000 1.80000 29.84 0.60178  8 416.8615018.270 1.49700 81.54 0.53748  9 −440.71712 0.125  10 999.99521 10.8291.63246 63.77 0.54215  11 −1249.81060 35.076  12 341.50810 23.0001.43387 95.18 0.53733  13 −555.44540 1.826  14 218.29118 6.257 1.6200436.26 0.58800  15 143.35678 28.012 1.43875 94.94 0.53433  16 9804.770773.126  17 172.79153 17.500 1.43875 94.94 0.53433  18 472.57533 DD [18] 19 184.30388 4.485 1.95375 32.32 0.59015  20 86.21375 12.779  21−327.42076 3.061 1.55032 75.50 0.54001  22 61.43736 4.500 1.54814 45.780.56859  23 77.86458 9.830  24 −144.01651 2.155 1.49700 81.54 0.53748 25 96.10729 7.000 1.84139 24.56 0.61274  26 −679.42572 5.898  27−75.75003 2.125 1.43875 94.94 0.53433  28 1478.43455 DD [28]  294567.42296 7.086 1.43875 94.66 0.53402  30 −138.46671 0.166  312111.50348 7.813 1.43875 94.66 0.53402  32 −126.19862 2.268 1.9465232.80 0.58853  33 −185.32437 DD [33]  34 124.52210 6.889 1.80381 32.490.59305  35 90.89636 10.023 1.43875 94.66 0.53402  36 −186927.497992.117  37 829.24124 6.060 1.43875 94.66 0.53402 *38 −343.97598 DD [38] 39 ∞ 7.702 (diaphragm)  40 −170.75799 4.421 1.51777 61.27 0.54254  411475.89688 1.393  42 850.55831 4.352 1.84139 24.56 0.61274  43−305.31634 3.654 1.83481 42.72 0.56486  44 413.48017 22.576  45−124.89221 2.963 1.63709 35.15 0.58659  46 549.68685 5.103 1.84139 24.560.61274  47 −187.85314 0.562  48 59.64886 5.814 1.73577 53.93 0.54453 49 1254.69959 3.520 1.72411 29.00 0.60099  50 86.06614 19.253  51144.26045 7.882 1.74352 40.78 0.57414  52 −63.37168 2.504 1.92475 36.380.57718  53 98.95567 14.864  54 341.41408 5.047 1.84139 24.56 0.61274 55 −97.75851 13.082  56 221.61374 4.531 1.52295 50.71 0.55785  5721.13749 6.600 1.49700 81.54 0.53748  58 48.16130 8.031  59 94.871246.958 1.49700 81.54 0.53748  60 −37.45970 2.870 1.95375 32.32 0.59015 61 −258.87634 9.967  62 55.96570 4.807 1.53491 57.92 0.54796  63−390.17281 2.000  64 ∞ 1.500 1.51633 64.14 0.53531  65 ∞ 0.000  66 ∞3.690 1.51633 64.14 0.53531  67 ∞ 35.273

TABLE 10 Example 3, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 20.0 magnification f′ 34.989 134.359699.788 FNo. 2.85 2.85 4.85 2ω[°] 44.4 11.8 2.2

TABLE 11 Example 3, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 5.867 85.721 118.204 DD [28] 232.487 133.483 3.402DD [33] 24.441 5.855 2.323 DD [38] 2.695 40.431 141.560

TABLE 12 Example 3, aspherical coefficient Surface number 38 KA−6.0659990E+00   A3 0.0000000E+00 A4 7.5934682E−09 A5 −1.2082285E−09  A6 5.9533640E−11 A7 5.6310087E−14 A8 6.4475101E−14 A9 −1.0442256E−14  A10 6.3094636E−17 A11 2.0953831E−17 A12 −6.5812003E−19   A135.7283785E−21 A14 −1.3871386E−22   A15 6.1553364E−24 A16−6.9270089E−26  

A zoom lens according to Example 4 is described next. FIG. 4 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 4.

The zoom lens according to Example 4 differs from the zoom lensaccording to Example 1 only for the lens number configuration of a firstlens group G1. The first lens group G1 is composed of a 1 a lens groupG1 a consisting of three lenses of a lens L1 a to a lens L1 c, a 1 blens group G1 b consisting of two lenses of a lens L1 d and a lens L1 e,and a 1 c lens group G1 c consisting of five lenses of a lens L1 f to alens L1 j.

Table 13 shows basic lens data of the zoom lens according to Example 4,Table 14 shows data relating to specifications, Table 15 shows datarelating to surface distances that change, and Table 16 shows datarelating to aspherical coefficients. FIG. 14 shows aberrations.

TABLE 13 Example 4, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 1203.32487 4.400 1.8830040.76 0.56679  2 388.55765 22.500  3 −592.83878 4.400 1.65113 55.890.54672  4 307.63955 3.009  5 329.25013 13.266 1.84139 24.56 0.61274  61422.51599 2.995  7 1227.16435 7.230 1.54072 47.23 0.56511  8 303.5355328.076 1.43875 94.94 0.53433  9 −436.87379 47.872 10 411.84229 11.2511.69400 56.29 0.54506 11 ∞ 8.520 12 221.02501 20.000 1.43387 95.180.53733 13 3784.25046 0.250 14 253.15612 7.500 1.69895 30.05 0.60290 15127.15122 30.030 1.43875 94.94 0.53433 16 2555.29938 5.000 17 168.8585711.910 1.49700 81.54 0.53748 18 385.87126 DD [18] 19 2766.24481 3.2501.71299 53.87 0.54587 20 64.32982 12.471 21 −200.04038 1.820 1.8348142.72 0.56486 22 131.40042 3.000 1.84139 24.56 0.61274 23 227.277734.788 24 −263.90206 2.032 1.49700 81.54 0.53748 25 96.99160 7.8181.78472 25.68 0.61621 26 −394.03764 5.500 27 −97.99682 2.000 1.4387594.94 0.53433 28 −2704.70097 DD [28] 29 571.03169 7.574 1.43875 94.660.53402 30 −175.34201 0.125 31 −5273.85855 9.925 1.43875 94.66 0.5340232 −99.81994 3.000 1.80000 29.84 0.60178 33 −143.78222 DD [33] 34288.39088 4.000 1.80000 29.84 0.60178 35 189.38496 6.545 1.43875 94.660.53402 36 −1294.84337 0.757 37 195.15150 9.750 1.43875 94.66 0.53402*38  −3419.85116 DD [38] 39 (diaphragm) ∞ 7.602 40 −154.21325 1.5201.83481 42.72 0.56486 41 1055.59942 2.568 1.84139 24.56 0.61274 42−481.20610 0.200 43 75.70122 4.890 1.56384 60.83 0.54082 44 242.8154136.671 45 −2628.86635 2.000 1.80610 33.27 0.58845 46 97.76108 3.437 47−173.65554 2.443 1.95906 17.47 0.65993 48 −87.49658 0.300 49 52.595635.624 1.77250 49.62 0.55186 50 −130.79828 1.306 1.53172 48.84 0.56558 5139.25083 4.064 52 −1280.59765 4.032 1.63854 55.38 0.54858 53 −44.127841.000 1.95375 32.32 0.59015 54 121.20174 13.118 55 119.12162 4.4161.84139 24.56 0.61274 56 −95.72269 8.375 57 −129.53488 3.388 1.5120052.12 0.56018 58 20.51211 18.000 1.49700 81.54 0.53748 59 36.16294 2.32360 58.70246 7.174 1.49700 81.54 0.53748 61 −42.75542 1.526 2.00100 29.130.59952 62 −166.65679 10.250 63 51.72062 6.662 1.51742 52.43 0.55649 64−117.33300 2.000 65 ∞ 1.500 1.51633 64.14 0.53531 66 ∞ 0.000 67 ∞ 3.6901.51633 64.14 0.53531 68 ∞ 33.477

TABLE 14 Example 4, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 19.6 magnification f′ 34.589 132.822677.946 FNo. 2.85 2.85 4.76 2ω[°] 45.4 12.0 2.4

TABLE 15 Example 4, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 8.534 82.112 114.634 DD [28] 242.787 134.807 4.410DD [33] 9.113 3.407 2.249 DD [38] 2.730 42.838 141.870

TABLE 16 Example 4, aspherical coefficient Surface number 38 KA1.0000000E+00 A3 0.0000000E+00 A4 −4.7142041E−08   A5 2.3491920E−08 A6−4.2313783E−09   A7 4.0862089E−10 A8 −2.4055326E−11   A9 9.6758230E−13A10 −2.9523189E−14   A11 6.1417894E−16 A12 6.1911610E−19 A13−5.8240543E−19   A14 1.9090551E−20 A15 −2.7279816E−22   A161.5134108E−24

A zoom lens according to Example 5 is described next. FIG. 5 providescross-sectional sectional views illustrating a lens configuration of thezoom lens according to Example 5. The zoom lens according to Example 5has the same lens number configuration as that of the zoom lensaccording to Example 4. Table 17 shows basic lens data of the zoom lensaccording to Example 5, Table 18 shows data relating to specifications,Table 19 shows data relating to surface distances that change, and Table20 shows data relating to aspherical coefficients. FIG. 15 showsaberrations.

TABLE 17 Example 5, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 1274.22298 4.400 1.8830040.76 0.56679  2 326.74501 19.684  3 −548.17143 4.400 1.65113 55.890.54672  4 279.55876 2.619  5 295.45890 12.485 1.84139 24.56 0.61274  61744.32995 4.294  7 2819.10370 5.030 1.54072 47.23 0.56511  8 353.7368725.000 1.43875 94.94 0.53433  9 −334.96231 38.468 10 364.50249 12.7911.69400 56.29 0.54506 11 ∞ 4.393 12 222.74581 18.826 1.43387 95.180.53733 13 3082.74950 0.165 14 303.40519 5.054 1.69895 30.05 0.60290 15132.44104 29.250 1.43875 94.94 0.53433 16 3846.74680 5.000 17 169.8265913.641 1.49700 81.54 0.53748 18 483.48570 DD [18] 19 617.86280 2.9771.71299 53.87 0.54587 20 65.00898 11.459 21 −503.11416 1.820 1.8348142.72 0.56486 22 153.06550 3.000 1.84139 24.56 0.61274 23 298.423995.513 24 −159.10770 2.032 1.49700 81.54 0.53748 25 96.50142 7.2181.78472 25.68 0.61621 26 −681.45993 7.903 27 −83.70584 2.000 1.4387594.94 0.53433 28 637.96362 DD [28] 29 2166.99695 6.963 1.43875 94.660.53402 30 −161.11101 0.125 31 −405.05862 7.540 1.43875 94.66 0.53402 32−105.61287 3.000 1.80000 29.84 0.60178 33 −144.13129 DD [33] 34242.43997 4.431 1.80000 29.84 0.60178 35 151.75864 7.723 1.43875 94.660.53402 36 −2815.57106 0.757 37 181.60265 10.556 1.43875 94.66 0.53402*38  −377.38727 DD [38] 39 (diaphragm) ∞ 9.860 40 −133.65484 1.5201.83481 42.72 0.56486 41 288.73885 3.709 1.84139 24.56 0.61274 42−382.22988 0.632 43 78.52091 6.301 1.57328 61.52 0.54253 44 155.1964537.811 45 1799.38883 2.114 1.78321 25.97 0.60975 46 87.15520 3.914 47−531.25079 3.149 1.82905 26.59 0.60918 48 −100.44400 0.393 49 55.453928.694 1.71006 50.50 0.55448 50 −119.85496 1.310 1.56200 43.51 0.57039 5147.74047 3.703 52 551.26851 4.508 1.62780 49.87 0.56027 53 −52.329861.000 1.94317 33.43 0.58644 54 142.62331 12.620 55 118.28005 4.6031.85354 22.52 0.62153 56 −106.22412 9.303 57 −4540.69688 5.705 1.5177255.43 0.55082 58 20.05508 10.796 1.49700 81.54 0.53748 59 35.96189 4.75660 65.96374 12.822 1.49700 81.54 0.53748 61 −42.55351 1.200 1.9697930.71 0.59530 62 −2057.26456 8.437 63 60.38503 5.578 1.53899 52.350.55624 64 −107.26704 2.000 65 ∞ 1.500 1.51633 64.14 0.53531 66 ∞ 0.00067 ∞ 3.690 1.51633 64.05 0.53463 68 ∞ 33.854

TABLE 18 Example 5, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 19.6 magnification f′ 34.658 133.088679.304 FNo. 2.85 2.85 4.75 2ω[°] 44.8 11.8 2.4

TABLE 19 Example 5, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 2.263 82.338 117.906 DD [28] 234.237 130.599 6.030DD [33] 31.332 11.588 2.249 DD [38] 5.447 48.754 147.095

TABLE 20 Example 5, aspherical coefficient Surface number 38 KA1.0000000E+00 A3 0.0000000E+00 A4 2.5373147E−08 A5 −3.1896159E−09   A64.9719239E−10 A7 −3.4019825E−11   A8 9.1983859E−13 A9 1.0565892E−14 A10−1.3331255E−15   A11 3.5450551E−17 A12 −6.1939046E−19   A131.7369551E−20 A14 −4.7811217E−22   A15 6.8387262E−24 A16−3.7656702E−26  

A zoom lens according to Example 6 is described next. FIG. 6 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 6. The zoom lens according to Example 6 has thesame lens number configuration as that of the zoom lens according toExample 4. Table 21 shows basic lens data of the zoom lens according toExample 6, Table 22 shows data relating to specifications, Table 23shows data relating to surface distances that change, and Table 24 showsdata relating to aspherical coefficients. FIG. 16 shows aberrations.

TABLE 21 Example 6, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 2216.47396 4.400 1.8830040.76 0.56679  2 348.74419 21.647  3 −456.42458 4.400 1.65113 55.890.54672  4 335.83718 2.549  5 355.21879 13.626 1.84139 24.56 0.61274  6−16713.99573 2.832  7 2387.81519 7.230 1.54072 47.23 0.56511  8355.83781 26.378 1.43875 94.94 0.53433  9 −327.41035 38.235 10 379.4274912.852 1.69400 56.29 0.54506 11 ∞ 1.200 12 221.02097 20.000 1.4338795.18 0.53733 13 3782.88841 0.204 14 308.20464 7.227 1.69895 30.050.60290 15 132.61749 28.875 1.43875 94.94 0.53433 16 1868.31531 4.272 17169.86664 13.502 1.49700 81.54 0.53748 18 430.57733 DD [18] 191103.58993 3.250 1.71299 53.87 0.54587 20 68.01115 11.907 21 −326.983001.820 1.83481 42.72 0.56486 22 169.63947 2.628 1.84139 24.56 0.61274 23290.89410 5.315 24 −168.64444 2.032 1.49700 81.54 0.53748 25 102.429277.392 1.78472 25.68 0.61621 26 −400.80737 5.500 27 −89.08531 2.0001.43875 94.94 0.53433 28 591.05707 DD [28] 29 1022.51482 6.867 1.4387594.66 0.53402 30 −173.29128 0.125 31 −963.77281 8.813 1.43875 94.660.53402 32 −103.46118 3.000 1.80000 29.84 0.60178 33 −145.63723 DD [33]34 307.20795 4.000 1.80000 29.84 0.60178 35 187.24071 6.734 1.4387594.66 0.53402 36 −1295.29211 0.757 37 190.80292 9.750 1.43875 94.660.53402 *38  −574.80733 DD [38] 39 (diaphragm) ∞ 7.835 40 −157.054491.520 1.83481 42.72 0.56486 41 729.25837 2.638 1.84139 24.56 0.61274 42−554.56625 1.173 43 75.91858 5.086 1.56384 60.83 0.54082 44 249.9880741.357 45 −3774.71446 2.000 1.80610 33.27 0.58845 46 94.85869 3.623 47−173.43860 2.415 1.95906 17.47 0.65993 48 −86.94731 2.606 49 51.636915.569 1.77250 49.62 0.55186 50 −119.22975 1.220 1.53172 48.84 0.56558 5138.99544 3.956 52 −1598.56178 3.981 1.63854 55.38 0.54858 53 −42.953691.264 1.95375 32.32 0.59015 54 107.69108 13.785 55 117.37581 4.2351.84139 24.56 0.61274 56 −98.37784 8.474 57 −144.27087 3.922 1.5120052.12 0.56018 58 21.27734 17.951 1.49700 81.54 0.53748 59 36.86550 2.07060 54.29072 7.322 1.49700 81.54 0.53748 61 −46.00893 1.200 2.00100 29.130.59952 62 −179.99726 10.250 63 46.73203 6.560 1.51742 52.43 0.55649 64−180.74015 2.000 65 ∞ 1.500 1.51633 64.14 0.53531 66 ∞ 0.000 67 ∞ 3.6901.51633 64.05 0.53463 68 ∞ 32.967

TABLE 22 Example 6, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom 1.0 3.8 19.6 magnification f′ 35.510 136.357695.987 FNo. 2.86 2.86 4.75 2ω[°] 44.2 11.8 2.4

TABLE 23 Example 6, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 7.151 86.917 122.100 DD [28] 241.513 134.564 5.603DD [33] 24.459 8.405 2.178 DD [38] 2.711 45.948 145.953

TABLE 24 Example 6, aspherical coefficient Surface number 38 KA1.0000000E+00 A3 0.0000000E+00 A4 4.7590627E−09 A5 1.7107487E−09 A6−2.7096195E−10   A7 2.4286712E−11 A8 −1.2588015E−12   A9 3.9012037E−14A10 −9.7460038E−16   A11 3.1118871E−17 A12 −6.6381916E−19   A13−7.9197859E−21   A14 7.3028040E−22 A15 −1.3743077E−23   A168.7579813E−26

A zoom lens according to Example 7 is described next. FIG. 7 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 7. The zoom lens according to Example 7 has thesame lens number configuration as that of the zoom lens according toExample 4. Table 25 shows basic lens data of the zoom lens according toExample 7, Table 26 shows data relating to specifications, Table 27shows data relating to surface distances that change, and Table 28 showsdata relating to aspherical coefficients. FIG. 17 shows aberrations.

TABLE 25 Example 7, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 3115.22902 4.400 1.8830040.76 0.56679  2 349.55385 22.499  3 −388.68497 4.432 1.65113 55.890.54672  4 411.65471 2.342  5 429.44340 13.552 1.84139 24.56 0.61274  6−1689.09587 2.687  7 2385.11397 7.230 1.54072 47.23 0.56511  8 357.6230826.396 1.43875 94.94 0.53433  9 −318.17967 38.273 10 368.41048 13.1431.69400 56.29 0.54506 11 ∞ 2.653 12 220.84589 19.997 1.43387 95.180.53733 13 3693.07273 0.224 14 313.75805 7.240 1.69895 30.05 0.60290 15131.42301 28.304 1.43875 94.94 0.53433 16 1146.73703 3.740 17 164.7520813.328 1.49700 81.54 0.53748 18 414.73079 DD [18] 19 1326.38078 3.1831.71299 53.87 0.54587 20 67.44942 12.498 21 −286.53431 1.820 1.8348142.72 0.56486 22 188.08010 2.110 1.84139 24.56 0.61274 23 275.094485.138 24 −176.55465 2.032 1.49700 81.54 0.53748 25 100.95140 7.7021.78472 25.68 0.61621 26 −329.77942 5.500 27 −88.87861 2.000 1.4387594.94 0.53433 28 714.95128 DD [28] 29 928.29470 7.168 1.43875 94.660.53402 30 −166.00053 0.125 31 −1289.47173 8.913 1.43875 94.66 0.5340232 −103.32262 3.000 1.80000 29.84 0.60178 33 −148.26931 DD [33] 34308.89930 4.000 1.80000 29.84 0.60178 35 192.07672 6.038 1.43875 94.660.53402 36 −1294.71907 0.757 37 196.66541 9.750 1.43875 94.66 0.53402*38  −720.72252 DD [38] 39 (diaphragm) ∞ 7.195 40 −156.68264 1.5201.83481 42.72 0.56486 41 842.45166 2.150 1.84139 24.56 0.61274 42−586.07745 0.200 43 75.34448 4.999 1.56384 60.83 0.54082 44 249.9949342.069 45 −2883.82574 2.000 1.80610 33.27 0.58845 46 94.42916 3.286 47−178.38958 2.280 1.95906 17.47 0.65993 48 −87.12464 4.073 49 51.009595.290 1.77250 49.62 0.55186 50 −121.12174 1.222 1.53172 48.84 0.56558 5138.98139 3.994 52 −1400.07367 3.970 1.63854 55.38 0.54858 53 −42.710931.000 1.95375 32.32 0.59015 54 98.29809 13.516 55 107.32507 4.2651.84139 24.56 0.61274 56 −99.07220 8.352 57 −142.68824 4.922 1.5120052.12 0.56018 58 21.77806 18.000 1.49700 81.54 0.53748 59 37.19255 1.68260 52.96086 7.467 1.49700 81.54 0.53748 61 −45.25620 1.200 2.00100 29.130.59952 62 −177.03293 9.775 63 49.57904 6.438 1.51742 52.43 0.55649 64−157.84741 2.000 65 ∞ 1.500 1.51633 64.14 0.53531 66 ∞ 0.000 67 ∞ 3.6901.51633 64.05 0.53463 68 ∞ 32.964

TABLE 26 Example 7, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom magnification 1.0 3.8 19.6 f′ 35.753 137.290700.753 FNo. 2.93 2.93 4.80 2ω[°] 44.0 11.6 2.4

TABLE 27 Example 7, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 6.643 87.122 121.889 DD [28] 242.174 135.517 5.350DD [33] 24.794 8.161 2.147 DD [38] 2.646 45.457 146.871

TABLE 28 Example 7, aspherical coefficient Surface number 38 KA1.0000000E+00 A3 0.0000000E+00 A4 −2.0798385E−08  A5 1.4657683E−08 A6−3.2730034E−09  A7 3.7528927E−10 A8 −2.3490790E−11  A9 7.3529647E−13 A10−3.8695741E−15  A11 −4.2162522E−16  A12 7.4099281E−18 A13 2.5167013E−19A14 −1.1222166E−20  A15 1.6156810E−22 A16 −8.4641640E−25 

A zoom lens according to Example 8 is described next. FIG. 8 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 8. The zoom lens according to Example 8 has thesame lens number configuration as that of the zoom lens according toExample 4. Table 29 shows basic lens data of the zoom lens according toExample 8, Table 30 shows data relating to specifications, Table 31shows data relating to surface distances that change, and Table 32 showsdata relating to aspherical coefficients. FIG. 18 shows aberrations.

TABLE 29 Example 8, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF   1 3419.25761 4.400 1.8830040.76 0.56679   2 268.72262 22.500   3 −325.39718 4.400 1.65113 55.890.54672   4 849.27595 1.590   5 554.83719 12.404 1.84139 24.56 0.61274  6 −772.13620 2.583   7 2822.49348 7.230 1.54072 47.23 0.56511   8349.62856 25.000 1.43875 94.94 0.53433   9 −324.61950 37.610  10342.27383 13.390 1.69400 56.29 0.54506  11 ∞ 1.200  12 221.03333 18.8921.43387 95.18 0.53733  13 3787.89946 0.150  14 296.51832 7.228 1.6989530.05 0.60290  15 125.50723 27.114 1.43875 94.94 0.53433  16 1067.286941.925  17 160.13272 13.806 1.49700 81.54 0.53748  18 439.05795 DD [18] 19 2935.50028 2.539 1.71299 53.87 0.54587  20 61.35000 10.412  21−282.10249 1.820 1.83481 42.72 0.56486  22 216.47851 1.663 1.84139 24.560.61274  23 266.36370 5.213  24 −160.05160 2.032 1.49700 81.54 0.53748 25 96.07282 8.233 1.78472 25.68 0.61621  26 −320.14787 5.500  27−89.66922 2.000 1.43875 94.94 0.53433  28 −1822.66535 DD [28]  29819.89128 7.442 1.43875 94.66 0.53402  30 −159.42426 0.125  31−1769.47221 9.550 1.43875 94.66 0.53402  32 −99.13897 3.000 1.8000029.84 0.60178  33 −145.00629 DD [33]  34 329.57600 4.000 1.80000 29.840.60178  35 207.75429 6.202 1.43875 94.66 0.53402  36 −1286.25470 0.757 37 193.19837 9.750 1.43875 94.66 0.53402 *38 −747.54203 DD [38]  39(diaphragm) ∞ 7.178  40 −150.83111 1.520 1.83481 42.72 0.56486  411285.21087 2.578 1.84139 24.56 0.61274  42 −402.71362 0.200  43 75.194564.658 1.56384 60.83 0.54082  44 233.70941 33.600  45 −3742.13758 2.4161.80610 33.27 0.58845  46 103.10491 3.370  47 −184.64656 2.369 1.9590617.47 0.65993  48 −91.36101 15.145  49 49.98841 4.815 1.77250 49.620.55186  50 −111.26701 1.360 1.53172 48.84 0.56558  51 36.04071 4.796 52 −1102.24855 3.551 1.63854 55.38 0.54858  53 −38.37127 1.000 1.9537532.32 0.59015  54 91.96782 25.244  55 84.97889 4.905 1.84139 24.560.61274  56 −116.46246 1.178  57 −334.60113 4.613 1.51200 52.12 0.56018 58 23.51602 17.561 1.49700 81.54 0.53748  59 32.71339 2.339  6050.00026 10.184 1.49700 81.54 0.53748  61 −35.25465 1.200 2.00100 29.130.59952  62 −170.98964 1.561  63 79.30993 6.391 1.51742 52.43 0.55649 64 −57.85791 2.000  65 ∞ 1.500 1.51633 64.14 0.53531  66 ∞ 0.000  67 ∞3.690 1.51633 64.05 0.53463  68 ∞ 33.445

TABLE 30 Example 8, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom magnification 1.0 3.8 19.6 f′ 34.588 132.820677.934 FNo. 2.90 2.90 4.87 2ω[°] 44.0 11.6 2.4

TABLE 31 Example 8, zoom distance Wide angle end Intermediate positionTelephoto end DD [18] 5.628 82.422 114.895 DD [28] 240.928 131.248 4.160DD [33] 34.219 23.606 2.072 DD [38] 2.586 46.085 162.234

TABLE 32 Example 8, aspherical coefficient Surface number 38 KA 1.0000000E+00 A3  0.0000000E+00 A4  4.9456135E−09 A5  2.3747287E−10 A6−1.9805341E−11 A7 −3.1856119E−13 A8  1.9296610E−13 A9 −1.6150477E−14 A10 5.7506215E−16 A11 −7.9406340E−18 A12  4.5796409E−20 A13 −4.6008535E−21A14  1.8723305E−22 A15 −2.6908389E−24 A16  1.2982256E−26

A zoom lens according to Example 9 is described next. FIG. 9 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 9. The zoom lens according to Example 9 has thesame lens number configuration as that of the zoom lens according toExample 4. Table 33 shows basic lens data of the zoom lens according toExample 9, Table 34 shows data relating to specifications, Table 35shows data relating to surface distances that change, and Table 36 showsdata relating to aspherical coefficients. FIG. 19 shows aberrations.

TABLE 33 Example 9, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 2717.73485 5.700 1.8830040.76 0.56679  2 380.86224 17.798  3 −726.84477 7.258 1.77250 49.600.55212  4 292.30100 15.088 1.84139 24.56 0.61274  5 3628.20361 2.930  62431.82575 7.530 1.54072 47.23 0.56511  7 371.94500 25.499 1.43875 94.940.53433  8 −340.46372 40.037  9 396.43767 12.437 1.77250 49.60 0.55212 10 ∞ 1.767  11 219.67124 18.668 1.43387 95.18 0.53733  12 2215.772551.371  13 369.04550 7.283 1.69895 30.13 0.60298  14 138.62300 27.5581.43875 94.94 0.53433  15 3628.23215 1.114  16 165.94924 15.000 1.4970081.54 0.53748  17 529.27566 DD [17]  18 1907.28239 3.250 1.69400 56.290.54506  19 65.14127 10.408  20 −551.87594 2.089 1.83481 42.72 0.56486 21 133.34200 3.000 1.84139 24.56 0.61274  22 225.37347 6.588  23−142.82782 2.108 1.49700 81.54 0.53748  24 97.56200 8.061 1.75520 27.510.61033  25 −346.22505 5.500  26 −88.09661 2.000 1.43875 94.94 0.53433 27 2023.15419 DD [27]  28 764.60970 7.656 1.43875 94.66 0.53402  29−160.39950 0.125  30 −2955.12791 9.628 1.43875 94.66 0.53402  31−101.71700 3.000 1.80000 29.84 0.60178  32 −149.23719 DD [32]  33343.80179 4.000 1.80000 29.84 0.60178  34 215.03300 6.274 1.43875 94.660.53402  35 −950.99135 0.757  36 207.51344 9.750 1.43875 94.66 0.53402*37 −945.77432 DD [37]  38 (diaphragm) ∞ 6.570  39 −121.16239 1.5201.83481 42.72 0.56486  40 890.64800 1.744 1.84139 24.56 0.61274  412481.54127 0.201  42 71.95464 6.910 1.56883 56.04 0.54853  43 −783.0374337.160  44 −3949.97334 2.001 1.91100 35.22 0.58360  45 79.02038 6.315 46 −136.72834 2.364 1.94595 17.98 0.65460  47 −84.05991 0.300  4839.78194 5.517 1.74950 35.28 0.58704  49 −605.08400 1.211 1.53172 48.840.56558  50 43.19462 7.880  51 471.91802 4.027 1.67790 55.34 0.54726  52−43.48600 1.001 1.91100 35.22 0.58360  53 72.66977 12.993  54 88.252535.643 1.84139 24.56 0.61274  55 −114.64819 5.753  56 −169.31860 2.9271.51200 52.12 0.56018  57 21.49700 17.948 1.49700 81.54 0.53748  5839.43278 1.615  59 46.61676 10.195 1.49700 81.54 0.53748  60 −35.786002.572 2.00069 25.46 0.61364  61 −180.29164 10.205  62 48.67158 7.1591.75550 45.59 0.55875  63 239.34644 2.000  64 ∞ 1.500 1.51633 64.140.53531  65 ∞ 0.000  66 ∞ 3.690 1.51633 64.14 0.53531  67 ∞ 32.404

TABLE 34 Example 9, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom magnification 1.0 3.8 19.6 f′ 35.351 135.746692.872 FNo. 2.85 2.85 4.86 2ω[°] 44.6 11.8 2.4

TABLE 35 Example 9, zoom distance Wide angle end Intermediate positionTelephoto end DD [17] 10.362 89.256 123.753 DD [27] 240.405 133.2955.060 DD [32] 26.561 10.750 2.240 DD [37] 3.448 47.476 149.724

TABLE 36 Example 9, aspherical coefficient Surface number 37 KA1.0000000E+00 A3 0.0000000E+00 A4 4.6291418E−09 A5 −2.5245283E−11  A61.8599768E−12 A7 −1.8274275E−13  A8 1.2282884E−15 A9 4.1929562E−16 A10−9.0843634E−18  A11 −2.8977192E−19  A12 2.0924759E−21 A13 3.7948885E−22A14 −4.1745995E−24  A15 −1.3050865E−25  A16 1.9473717E−27

A zoom lens according to Example 10 is described next. FIG. 10 providescross-sectional views illustrating a lens configuration of the zoom lensaccording to Example 10. The zoom lens according to Example 10 has thesame lens number configuration as that of the zoom lens according toExample 4. Table 37 shows basic lens data of the zoom lens according toExample 10, Table 38 shows data relating to specifications, Table 39shows data relating to surface distances that change, and Table 40 showsdata relating to aspherical coefficients. FIG. 20 shows aberrations.

TABLE 37 Example 10, lens data (nd, νd for d-line) Surface numberCurvature radius Surface distance nd νd θgF  1 2821.04454 5.700 1.8830040.76 0.56679  2 381.28602 17.714  3 −749.98024 7.258 1.77250 49.600.55212  4 287.45401 15.400 1.84139 24.56 0.61274  5 3786.57187 3.037  62684.13160 7.258 1.54072 47.23 0.56511  7 375.07381 25.623 1.43875 94.940.53433  8 −336.45223 40.110  9 387.29043 12.707 1.77250 49.60 0.55212 10 ∞ 1.200  11 218.89802 18.721 1.43387 95.18 0.53733  12 2189.414191.633  13 390.73134 7.280 1.69895 30.13 0.60298  14 138.96143 27.4121.43875 94.94 0.53433  15 3635.93962 4.732  16 163.67600 15.000 1.4970081.54 0.53748  17 526.91202 DD [17]  18 2249.39184 3.250 1.69400 56.290.54506  19 65.53556 10.119  20 −549.71572 1.820 1.83481 42.72 0.56486 21 133.34592 3.000 1.84139 24.56 0.61274  22 229.66815 6.263  23−144.76978 2.032 1.49700 81.54 0.53748  24 96.97187 7.943 1.75520 27.510.61033  25 −349.60908 5.500  26 −88.00025 2.000 1.43875 94.94 0.53433 27 1998.83442 DD [27]  28 760.48326 7.677 1.43875 94.66 0.53402  29−159.54485 0.125  30 −2858.23392 9.662 1.43875 94.66 0.53402  31−101.02816 3.000 1.80000 29.84 0.60178  32 −149.81389 DD [32]  33340.11532 4.000 1.80000 29.84 0.60178  34 219.50376 6.260 1.43875 94.660.53402  35 −907.02141 0.810  36 211.78810 9.785 1.43875 94.66 0.53402*37 −1035.82026 DD [37]  38 (diaphragm) ∞ 8.841  39 −154.31467 1.5201.83481 42.72 0.56486  40 866.36903 1.894 1.84139 24.56 0.61274  41 ∞0.200  42 70.46066 5.210 1.57250 57.74 0.54568  43 249.98594 37.750  44−1045.94314 2.023 1.88100 40.14 0.57010  45 126.19585 3.026  46−249.99766 2.482 1.95906 17.47 0.65993  47 −106.36791 2.508  48 46.207076.695 1.78800 47.37 0.55598  49 −137.32023 1.265 1.51200 52.12 0.56018 50 40.99770 7.881  51 −3794.31214 3.748 1.66999 51.72 0.55362  52−44.84376 1.102 1.95375 32.32 0.59015  53 62.98844 12.025  54 72.847189.864 1.84139 24.56 0.61274  55 −141.37310 4.543  56 −127.87204 3.3681.51200 52.12 0.56018  57 21.05592 17.703 1.49700 81.54 0.53748  5834.99882 2.028  59 50.00097 8.232 1.49700 81.54 0.53748  60 −36.260751.300 2.00100 29.13 0.59952  61 −139.97480 9.510  62 59.29004 7.4081.61405 54.99 0.55092  63 −118.86952 2.000  64 ∞ 1.500 1.51633 64.140.53531  65 ∞ 0.000  66 ∞ 3.690 1.51633 64.05 0.53463  67 ∞ 33.351

TABLE 38 Example 10, specifications (d-line) Wide angle end Intermediateposition Telephoto end Zoom magnification 1.0 3.8 19.6 f′ 35.348 135.736692.819 FNo. 2.85 2.85 4.75 2ω[°] 44.2 11.8 2.4

TABLE 39 Example 10, zoom distance Wide angle end Intermediate positionTelephoto end DD [17] 7.230 87.035 121.397 DD [27] 241.996 135.033 4.977DD [32] 24.645 8.820 2.229 DD [37] 2.753 45.735 148.020

TABLE 40 Example 10, aspherical coefficient Surface number 37 KA1.0000000E+00 A3 0.0000000E+00 A4 5.4418965E−09 A5 −2.8145484E−09  A64.9748646E−10 A7 −3.8597730E−11  A8 1.4954479E−12 A9 −2.9419974E−14  A103.5436025E−16 A11 −1.8610537E−18  A12 −3.0741467E−19  A13 9.2999539E−21A14 1.1878876E−22 A15 −7.1645004E−24  A16 6.8958760E−26

Table 41 shows values corresponding to the conditional expressions (1)to (9) of the zoom lenses according to Examples 1 to 10. In allexamples, the d-line is used as the reference wavelength. The valuesshown in Table 41 provided below are for the reference wavelength.

TABLE 41 Expression No. Conditional expression Example 1 Example 2Example 3 Example 4 Example 5 (1) (L2bpr + L2cnf)/(L2bpr − L2cnf) −0.301−0.301 −0.298 −0.075 0.304 (2) f2/f2a 0.261 0.261 0.262 0.493 0.449 (3)f2/f2b 0.403 0.403 0.400 0.358 0.204 (4) f2*(f2cp_nd −f2cn_nd)*(1/L2cnp) −0.164 −0.164 −0.163 −0.135 −0.137 (5) f1c_νd_ave90.6 86.1 95.0 82.0 82.0 (6) f1c_θ gF_ave 0.536 0.537 0.537 0.539 0.539(7) f1/f1c 1.014 1.025 1.011 1.037 1.060 (8) (L1ar + L1bf)/(L1ar − L1bf)−0.072 −0.046 −0.108 −0.208 −0.253 (9) d2/tt1 0.084 0.085 0.084 0.0990.096 Expression No. Conditional expression Example 6 Example 7 Example8 Example 9 Example 10 (1) (L2bpr + L2cnf)/(L2bpr − L2cnf) 0.266 0.2180.249 0.188 0.198 (2) f2/f2a 0.459 0.470 0.525 0.476 0.480 (3) f2/f2b0.254 0.279 0.282 0.241 0.240 (4) f2*(f2cp_nd − f2cn_nd)*(1/L2cnp)−0.131 −0.134 −0.138 −0.122 −0.124 (5) f1c_νd_ave 82.0 82.0 82.0 80.380.3 (6) f1c_θ gF_ave 0.539 0.539 0.539 0.540 0.540 (7) f1/f1c 1.0421.026 1.012 1.069 1.064 (8) (L1ar + L1bf)/(L1ar − L1bf) −0.134 −0.053−0.095 −0.312 −0.326 (9) d2/tt1 0.103 0.107 0.112 0.086 0.084

Referring to the above data, it is found that all the zoom lensesaccording to

Examples 1 to 10 are high-performance zoom lenses which satisfy theconditional expressions (1) to (9), which have high magnification of 15or more and a F-number of 5 or less at the telephoto end, and whoseaberrations have been properly corrected.

An imaging apparatus according to an embodiment of the invention isdescribed next. FIG. 21 is a schematic configuration diagram of animaging apparatus using a zoom lens according to an embodiment of theinvention, as an example of an imaging apparatus according to anembodiment of the invention. FIG. 21 schematically illustratesrespective lens groups. The imaging apparatus may be, for example, avideo camera or an electronic still camera including a solid-stateimaging element, such as a charge coupled device (CCD) or acomplementary metal oxide semiconductor (CMOS).

An imaging apparatus 10 illustrated in FIG. 21 includes a zoom lens 1, afilter 6 that is arranged on the image side of the zoom lens 1 and thathas a function of a low pass filter or the like, an imaging element 7arranged on the image side of the filter 6, and a signal processingcircuit 8. The imaging element 7 is for converting an optical imageformed by the zoom lens 1 into an electric signal. For example, CCD orCMOS can be used for the imaging element 7. The imaging element 7 isarranged such that an imaging surface of the imaging element 7 isaligned with the image surface of the zoom lens 1.

An image captured by the zoom lens 1 forms an image on the imagingsurface of the imaging element 7, an output signal from the imagingelement 7 relating to the image is arithmetically processed by thesignal processing circuit 8, and the image is displayed on a displaydevice 9.

Since the imaging apparatus 10 according to this embodiment includes thezoom lens 1 according to the invention, an image with high magnificationand high image quality can be obtained.

While the invention has been described above by using the embodimentsand examples; however, the invention is not limited to the embodimentsand examples, and may be modified in various ways. For example, thevalues of curvature radius, surface distance, refractive index, and/orAbbe number of each lens are not limited to the values provided in eachof the numerical examples, and may have other values.

REFERENCE SIGNS LIST

-   zoom lens-   filter-   imaging element-   signal processing circuit-   display device-   imaging apparatus-   G1 first lens group-   G1 a 1 a lens group-   G1 b 1 b lens group-   G1 c 1 c lens group-   G2 second lens group-   G3 third lens group-   G4 fourth lens group-   G5 fifth lens group-   PP1, PP2 optical member-   L1 a to L5 o lens-   Sim image surface-   St aperture diaphragm-   wa axial ray-   wb ray at maximum angle of view-   Z optical axis

What is claimed is:
 1. A zoom lens, consisting of: in order from anobject side, a first lens group having a positive refractive power, asecond lens group having a negative refractive power, a third lens grouphaving a positive refractive power, a fourth lens group having apositive refractive power, and a fifth lens group having a positiverefractive power, wherein during zooming, the first lens group is fixedrelative to an image surface, wherein during zooming from a wide angleend to a telephoto end, a distance between the first lens group and thesecond lens group constantly increases, a distance between the secondlens group and the third lens group constantly decreases, and a distancebetween the third lens group and the fourth lens group at the telephotoend is smaller than a distance between the third lens group and thefourth lens group at the wide angle end, wherein the second lens groupconsists of, in order from the object side, a first lens component, asecond lens component, a third lens component, and a fourth lenscomponent, wherein the first lens component is a 2a negative lens havinga concave surface that faces an image side and that has a smallerabsolute value of a curvature radius than an absolute value of acurvature radius of a surface on the object side of the 2a negativelens, wherein the second lens component is a cemented lens in which a2bn biconcave lens and a 2bp positive meniscus lens are cemented in thatorder from the object side and which entirely has a negative refractivepower, wherein the third lens component is a cemented lens in which a2cn biconcave lens and a 2cp positive lens are cemented in that orderfrom the object side, and wherein the fourth lens component is a 2dnegative lens having a concave surface that faces the object side andthat has a smaller absolute value of a curvature radius than an absolutevalue of a curvature radius of a surface on the image side of the 2dnegative lens.
 2. The zoom lens according to claim 1, wherein duringzooming, the fifth lens group is fixed relative to the image surface,and wherein during zooming from the wide angle end to the telephoto end,a 3-4 composite lens group composed of the third lens group and thefourth lens group, and the second lens group simultaneously pass throughrespective points at which imaging magnifications of the 3-4 compositelens group and the second lens group are −1.
 3. The zoom lens accordingto claim 1, wherein during zooming from the wide angle end to thetelephoto end, the distance between the third lens group and the fourthlens group decreases, increases, and then decreases.
 4. The zoom lensaccording to claim 1, wherein the 2a negative lens is a meniscus lens.5. The zoom lens according to claim 1, wherein the following conditionalexpression (1) is satisfied−1<(L2bpr+L2cnf)/(L2bpr−L2cnf)<1   (1), where L2bpr is a curvatureradius of a surface on the image side of the 2bp positive meniscus lens,and L2cnf is a curvature radius of a surface on the object side of the2cn biconcave lens.
 6. The zoom lens according to claim 1, wherein thefollowing conditional expressions (2) and (3) are satisfied0.2<f2/f2a<0.6   (2), and0.1<f2/f2b<0.6   (3), where f2 is a focal length for a d-line of thesecond lens group, f2a is a focal length for the d-line of the firstlens component, and f2b is a focal length for the d-line of the secondlens component.
 7. The zoom lens according to claim 1, wherein thefollowing conditional expression (4) is satisfied−0.3<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.1   (4), where f2 is the focallength for the d-line of the second lens group, f2cp_nd is a refractiveindex for the d-line of the 2cp positive lens, f2cn_nd is a refractiveindex for the d-line of the 2cn biconcave lens, and L2cnp is a curvatureradius of a cemented surface of the 2cn biconcave lens and the 2cppositive lens.
 8. The zoom lens according to claim 1, wherein the firstlens group consists of, in order from the object side, a 1 a lens groupfixed relative to the image surface during focusing and having anegative refractive power, a 1 b lens group being movable along anoptical axis during focusing and having a positive refractive power, anda 1 c lens group fixed relative to the image surface during focusing andhaving a positive refractive power, and wherein the 1 c lens group hason the most image side four lenses of, in order from the object side, apositive lens, a cemented lens in which a negative meniscus lens havinga convex surface facing the object side and a positive lens are cementedin that order from the object side, and a positive meniscus lens havinga convex surface facing the object side.
 9. The zoom lens according toclaim 8, wherein the following conditional expressions (5) and (6) aresatisfied75<f1c_vd_ave<96   (5), and0.5<f1c_θgF_ave<0.6   (6), where f1c_vd_ave is an average value of Abbenumbers for the d-line of the positive lenses included in the 1 c lensgroup, and f1c_θgF_ave is an average value of partial dispersion ratiosof the positive lenses included in the 1 c lens group.
 10. The zoom lensaccording to claim 8, wherein the following conditional expression (7)is satisfied0.8<f1/f1c<1.2   (7), where f1is a focal length for the d-line of thefirst lens group, and f1c is a focal length for the d-line of the 1 clens group.
 11. The zoom lens according to claim 8, wherein the numberof positive lenses included in the 1 b lens group and the 1 c lens groupis five in total.
 12. The zoom lens according to claim 11, wherein the 1b lens group consists of, in order from the object side, a cemented lensin which a negative meniscus lens and a biconvex lens are cemented inthat order from the object side, and a biconvex lens, and wherein the 1c lens group consists of, in order from the object side, a biconvexlens, a cemented lens in which a negative meniscus lens and a positivemeniscus lens are cemented in that order from the object side, and apositive meniscus lens.
 13. The zoom lens according to claim 11, whereinthe 1 b lens group consists of a cemented lens in which a negativemeniscus lens and a biconvex lens are cemented in that order from theobject side, and wherein the 1 c lens group consists of, in order fromthe object side, a positive lens having a convex surface facing theobject side, a positive meniscus lens, a cemented lens in which anegative meniscus lens and a positive meniscus lens are cemented in thatorder from the object side, and a positive meniscus lens.
 14. The zoomlens according to claim 8, wherein the 1 a lens group consists of, inorder from the object side, a negative meniscus lens, a biconcave lens,and a positive lens.
 15. The zoom lens according to claim 5, wherein thefollowing conditional expression (1-1) is satisfied−0.6<(L2bpr+L2cnf)/(L2bpr−L2cnf)<0.6   (1-1).
 16. The zoom lensaccording to claim 6, wherein the following conditional expression (2-1)and/or conditional expression (3-1) are satisfied25<f2/f2a<0.55   (2-1), and/or0.2<f2/f2b<0.5   (3-1).
 17. The zoom lens according to claim 7, whereinthe following conditional expression (4-1) is satisfied−0.2<f2×(f2cp_nd−f2cn_nd)×(1/L2cnp)<−0.12   (4-1).
 18. The zoom lensaccording to claim 9, wherein the following conditional expression (5-1)and/or conditional expression (6-1) are satisfied80<f1c_vd_ave<96   (5-1), and/or0.52<f1c_θgF_ave<0.56   (6-1).
 19. The zoom lens according to claim 10,wherein the following conditional expression (7-1) is satisfied0.9<f1/f1c<1.1   (7-1).
 20. An imaging apparatus comprising the zoomlens according to claim 1.